The phenomena of microbiological contamination of the oil and/or natural gas environment represent a broad problem. Microbial Contamination (MC) and Microbial Influenced Corrosion (MIC) both pose severe operational, environmental, and safety problems to the petroleum and/or natural gas industries, particularly with respect to degradation of the hydrocarbon products and corrosive damage of equipment used in the storage, processing, and/or transport of hydrocarbon products such as oil, gas, crude and/or processed materials.
First, the degradation of petroleum hydrocarbons is associated with the negative effect of microorganisms. The microbes use hydrocarbons contained in crude, oil and/or gas as a source of carbon and change the properties of this crude, oil and/or gas, thus reducing its value. For example, the changes in oil density, sulfur content and viscosity cause disruption in oil extraction and processing technology, bring about significant economic losses and cause adverse environmental effects. Industry research indicates that 10%-14% of oil and gas is lost due to Microbial Contamination.
Second, in addition to lowering the content of hydrocarbons in crude, oil and/or gas, problems also concern the ways crude, oil, natural gas and/or other petroleum products is stored, products of its processing, and drilling fluids. The adverse activity of microorganisms causes corrosion of transmission installations (e.g., oil or gas pipelines), producing undesirable substances (including H2S, polymers, organic acids, etc.) that affect the performance of oil and gas. Costs resulting from MC and MIC and biofilm formation in these industries occur due to repair and replacement of damaged equipment, spoiled oil, environmental clean-up, and injury-related health care, amount to well over several billion USD per year.
A variety of strategies have been developed to mitigate the negative effects of MC, MIC and/or the biofilms that contribute or cause MC and MIC. Such techniques include the use of corrosion resistant metals, temperature control, pH control, radiation, filtration, protective coatings with corrosion inhibitors, chemical controls (e.g., biocides, oxidizers, acids, alkalis), bacteriological controls (e.g., phages, enzymes, parasitic bacteria, antibodies, competitive microflora), pigging (i.e., mechanical delamination of corrosion products), anodic and cathodic protection, and modulation of nutrient levels. Attempts to eliminate microorganisms typically involve using chemicals exhibiting biocidal properties, which besides the physical methods is the most popular and most effective technique of eliminating Microbiological Contamination, Microbiological Influenced Corrosion and biofilm formation. However, the selection of appropriate antibacterial or antifungal agents requires the consideration of factors affecting the efficiency of the process. In fact, each of these existing methods face obstacles, such as, high cost, lack of effectiveness, short life-span, or requirement for repeat applications. For example, regular biocide injections are only effective sometimes and only in particular environments. In addition, biocides often fail due to incompatibility with other commonly used corrosion inhibitors and because of biofilm permeability issues, i.e., the biocides are unable to penetrate or permeate the biofilms due to the properties of the extracellular matrix of the biofilms. In addition, many of the above controls are not practical for implementing in the oil field due to the potential effect on the downstream processes.
In the oil field, pigging and biocides are the most commonly used approaches for controlling biofilms and corrosion. Pigging is required to remove or disrupt the biofilm on the pipe surfaces. Pigging can also remove many of the harmful iron sulfide deposits. While pigging will be substantially effective where thick biofilms are present, thin biofilms and thin iron sulfide deposits are not appreciably affected by the scraping action of pigs. Subsequently, biocides and surfactant biocide treatments are used extensively to control bacterial activity in oil field systems. However, biocides are not typically effective in penetrating the biofilms, and therefore, have reduced effectiveness against the underlying bacteria. Combination treatments in conjunction with pigging are more effective than the chemical treatments alone. However, treatments must be made routinely on a fixed schedule or else the bacteria population increases significantly, and control becomes even more difficult.
Thus, there exists a need in the art for an improved approach for inhibiting microbial concentration and/or biofilm formation that avoids the above indicated problems associated with existing methods, and in particular, which effectively reduces, mitigates, or otherwise eliminates Microbial Contamination, Microbial Influenced Corrosion and/or associated biofilms in/on oil and gas refinery equipment.